Priority substances and emerging pollutants in urban rivers in Ukraine: Occurrence, fluxes and loading to transboundary European Union watersheds.

The occurrence and fluxes of 18 priority substances and emerging pollutants listed in the European Union Water Framework Directive and a Watch List (trace metals (Cd, Pb and Ni), nonylphenols, octylphenols, 8 polyaromatic hydrocarbons, 4 dioxin-like polychlorinated biphenyls and diclofenac) were investigated in a Ukrainian city and the mass discharge loads of these compounds into EU-transboundary watersheds were estimated. Fluxes of chemicals were calculated per capita and per area of the Ukrainian urban territory and used to estimate mass loading of priority and emerging concern compounds from Lviv, Uzhorod and Chernivtsi (West Ukraine) to neighbouring EU-transboundary rivers. The highest loading was found for trace metals (1.15 t a-1), diclofenac (0.7 t a-1) and nonylphenols (0.4 t a-1). Transboundary water contamination must be considered in order to successfully manage water resources in a manner that fulfils the requirements of EU environmental quality standards.

Levodopa-induced dyskinesias and dopamine-dependent stereotypies: a new hypothesis.

The basal ganglia are thought to modulate the release or inhibition of movements by way of direct and indirect pathways that act as a push-pull system of cortico-basal ganglia circuits. Here we suggest a three-pathway model of the basal ganglia that takes into consideration the fundamental division of the striatum into striosomes and extrastriosomal matrix. We suggest that, in addition to the balance between direct and indirect pathways on which normal release of individual movements depends, the balance of activity between these matrix-based pathways and the striosomal pathway regulates the frequency of release of given behavioral sequences and, thus, modulates behavioral focus. Differential plasticity in these compartmentally organized circuits might contribute to the development of L-dopa-induced dyskinesias under parkinsonian conditions and dopamine-receptor-agonist induced stereotypies under normal conditions.

Extracellular matrix and development of lamination in the dorsal lateral geniculate nucleus in the tree shrew (Tupaia belangeri).

In the tree shrew (Tupaia belangeri), the cytoarchitectonic lamination of the lateral geniculate nucleus cannot be detected at birth; it only appears during the early postnatal period. However, a laminated pattern was revealed with rapid Golgi staining and retinal afferents were segregated into the appropriate laminae well before cytoarchitectonic lamination could be seen. Both observations indicate that the extracellular matrix may play a role in the separation of lateral geniculate nucleus cells into laminae. In the present study, the organization of the extracellular matrix was investigated during development using immunohistochemical and in situ hybridization techniques. For immunohistochemistry, peanut agglutinin (PNA) lectin and antibodies against tenascin (TN) were chosen, while for in situ hybridization, mTN riboprobes were used, simultaneously, with antibodies against Vimentin (Vim) and microtubule associated protein (MAP-2). The results showed that the pattern of PNA-binding glycoproteins and that of tenascin were relatively similar, although tenascin appeared later and disappeared earlier. The first interlaminar spaces to be detected were those between layers innervated by opposite eyes. The TN specific mRNA was detected in the lateral geniculate nucleus at P0, but was no longer visible at P7. By comparing TN mRNA and Vim or MAP-2 stainings a correspondence could be observed. The extracellular matrix lamination therefore seems to precede cytoarchitectonic lamination, suggesting that the extracellular matrix may play a role in the development of laminated structures. The TN-producing cells seem to be developing astrocytes and neurons.

Adaptive gene expression changes on the healthy side of parkinsonian rats.

Parkinson's disease (PD) is an asymmetric neurodegenerative disorder, and secondary adaptive mechanisms of the less-affected side could potentially compensate for parkinsonian symptoms. Here, we analyzed gene expression changes on the healthy side of a unilateral PD rat model and correlated these changes with locomotor velocity, which is known to be decreased in PD. Four weeks after a unilateral 6-hydroxydopamine lesion, the spontaneous locomotor velocity of rats was recorded just prior to brain extraction. We then analyzed the gene expression levels of markers of the direct (dynorphin and D1-class dopamine receptors) and indirect (enkephalin and D2-class dopamine receptors) pathways in the contralateral healthy striatum by in situ hybridization histochemistry. In addition, we analyzed the expression of several striatal and cortical glutamatergic markers, as well as nigral tyrosine hydroxylase (TH) and nigral dopamine transporter (DAT). We found a significant positive correlation between the mRNA expression levels of contralateral D1-class dopamine receptors and the mean locomotor velocity, at 4 weeks after surgery in parkinsonian rats but not in controls. Moreover, we observed a significant increase in the level of dynorphin mRNA in the lateral part of the contralateral striatum of parkinsonian rats compared to the controls. In contrast, no contralateral changes were observed in the striatal indirect pathway. We also did not find any significant contralateral modifications of TH, DAT or glutamatergic markers in PD animals, indicating that changes in direct pathway genes are not due to nigrostriatal dopaminergic or corticostriatal glutamatergic innervation. In conclusion, our results suggest a role of the healthy striatal direct pathway in counteracting dopaminergic denervation effects on motor symptoms.

Influence of the nature of the porphyrin ligand on the nuclease activity of metalloporphyrin-oligonucleotide conjugates designed with cationic, hydrophobic or anionic metalloporphyrins.

The synthesis of metalloporphyrin-oligonucleotide conjugates with different metalloporphyrin moieties are described as well as the comparison of their in vitro nuclease efficiency toward a single-stranded DNA target. Between cationic, anionic and hydrophobic manganese porphyrins covalently linked to the oligonucleotide, the best nuclease activity was obtained with the cationic ones, suggesting that the affinity of the cleaver to the DNA target is a key factor.

Improvement of porphyrin cellular delivery and activity by conjugation to a carrier peptide.

The chemical nuclease metalloporphyrin (manganese(III) porphyrin) can cleave DNA irreversibly and can thus constitute a potential antitumor drug. However, these molecules show low permeability to cell surface membranes. We report here the conjugation of an amphipathic carrier peptide to improve considerably its cellular delivery. The metalloporphyrin-peptide conjugate can be internalized by cells within only 5 min of incubation with a yield as high as 80%. Furthermore, the metalloporphyrin-peptide conjugate is able to cleave in vitro high or low molecular weight DNA to the same extend as metalloporphyrin alone without affecting the sequence-specific cleaving activity of the porphyrin. The conjugate is 100-fold more efficient at inducing tumor cells death than the free metalloporphyrin via a mechanism involving genomic DNA cleavage. The results are promising for further therapeutic applications with antitumor drugs such as metalloporphyrin, and also with other existing drugs by using a carrier peptide system in order to improve the cellular uptake of such molecules.

Targeting of a hydrophilic photosensitizer by use of internalizing monoclonal antibodies: A new possibility for use in photodynamic therapy.

Coupling of photosensitizers to tumor-selective monoclonal antibodies (MAbs) is an attractive option for improving the selectivity of photodynamic therapy (PDT). For this purpose, hydrophilic sensitizers would be most suitable because of their solubility in water. However, such sensitizers are known to be ineffective in PDT, probably because they cannot readily pass the cell membrane and reach the critical intracellular target. We used the model compound TrisMPyP-PhiCO(2)H, a hydrophilic porphyrin derivative, to test the hypothesis that hydrophilic photosensitizers might become of therapeutic value when directed into the tumor cell by use of internalizing MAbs. TrisMPyP-PhiCO(2)H was conjugated using a labile ester. Conjugates showed no impairment of integrity on SDS-PAGE, full stability in serum in vitro, and optimal immunoreactivity when the sensitizer:MAb ratio was

Shifts in striatal responsivity evoked by chronic stimulation of dopamine and glutamate systems.

Dopamine and glutamate are key neurotransmitters in cortico-basal ganglia loops affecting motor and cognitive function. To examine functional convergence of dopamine and glutamate neurotransmitter systems in the basal ganglia, we evaluated the long-term effects of chronic stimulation of each of these systems on striatal responses to stimulation of the other. First we exposed rats to chronic intermittent cocaine and used early-gene assays to test the responsivity of the striatum to subsequent acute motor cortex stimulation by application of the GABA(A) (gamma-aminobutyric acid alpha subunit) receptor antagonist, picrotoxin. Reciprocally, we studied the effects of chronic intermittent motor cortex stimulation on the capacity for subsequent acute dopaminergic treatments to induce early-gene activation in the striatum. Prior treatment with chronic intermittent cocaine induced motor sensitization and significantly potentiated the striatal expression of Fos-family early genes in response to stimulation of the motor cortex. Contrary to this, chronic intermittent stimulation of the motor cortex down-regulated cocaine-induced gene expression in the striatum, but enhanced striatal gene expression induced by a full D1 receptor agonist (SKF 81297) and did not change the early-gene response elicited by a D2 receptor antagonist (haloperidol). These findings suggests that repeated dopaminergic stimulation produces long-term enhancement of corticostriatal signalling from the motor cortex, amplifying cortically evoked modulation of the basal ganglia. By contrast, persistent stimulation of the motor cortex inhibits cocaine-stimulated signalling in the striatum, but not signalling mediated by individual dopamine receptor sites, suggesting that chronic cortical hyperexcitability produces long-term impairment of dopaminergic activity and compensation at the receptor level. These findings prompt a model of the basal ganglia function as being regulated by opposing homeostatic dopamine-glutamate neurotransmitter interactions. The model provides a framework for analysing the neurological alterations associated with disorders of the basal ganglia and their treatment with pharmacotherapies affecting dopamine and glutamate neurotransmitter systems.